From patchwork Thu Aug 23 18:27:59 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 961561 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 41xCdM2zpsz9ryt for ; Fri, 24 Aug 2018 04:30:15 +1000 (AEST) Received: from localhost ([::1]:38368 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fsuN3-0007vR-2J for incoming@patchwork.ozlabs.org; Thu, 23 Aug 2018 14:30:13 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49839) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fsuKv-0006lF-Ji for qemu-devel@nongnu.org; Thu, 23 Aug 2018 14:28:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fsuKu-0003ec-Bk for qemu-devel@nongnu.org; Thu, 23 Aug 2018 14:28:01 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:48036 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fsuKu-0003eM-6T for qemu-devel@nongnu.org; Thu, 23 Aug 2018 14:28:00 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DCA3E40216E7 for ; Thu, 23 Aug 2018 18:27:59 +0000 (UTC) Received: from gimli.home (ovpn-120-10.rdu2.redhat.com [10.10.120.10]) by smtp.corp.redhat.com (Postfix) with ESMTP id A8B52B27A9; Thu, 23 Aug 2018 18:27:59 +0000 (UTC) From: Alex Williamson To: qemu-devel@nongnu.org Date: Thu, 23 Aug 2018 12:27:59 -0600 Message-ID: <153504887923.3676.17354149092034837658.stgit@gimli.home> In-Reply-To: <153504858585.3676.10222732707932789866.stgit@gimli.home> References: <153504858585.3676.10222732707932789866.stgit@gimli.home> User-Agent: StGit/0.18-136-gffd7-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Thu, 23 Aug 2018 18:27:59 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Thu, 23 Aug 2018 18:27:59 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'alex.williamson@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PULL 3/3] postcopy: Synchronize usage of the balloon inhibitor X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" While the qemu_balloon_inhibit() interface appears rather general purpose, postcopy uses it in a last-caller-wins approach with no guarantee of balanced inhibits and de-inhibits. Wrap postcopy's usage of the inhibitor to give it one vote overall, using the same last-caller-wins approach as previously implemented at the balloon level. Fixes: 01ccbec7bdf6 ("balloon: Allow multiple inhibit users") Reported-by: Christian Borntraeger Tested-by: Christian Borntraeger Reviewed-by: Cornelia Huck Reviewed-by: Juan Quintela Signed-off-by: Alex Williamson --- migration/postcopy-ram.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index 932f18894990..c2e387ed44b4 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -509,6 +509,20 @@ int postcopy_ram_incoming_init(MigrationIncomingState *mis) return 0; } +/* + * Manage a single vote to the QEMU balloon inhibitor for all postcopy usage, + * last caller wins. + */ +static void postcopy_balloon_inhibit(bool state) +{ + static bool cur_state = false; + + if (state != cur_state) { + qemu_balloon_inhibit(state); + cur_state = state; + } +} + /* * At the end of a migration where postcopy_ram_incoming_init was called. */ @@ -539,7 +553,7 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis) mis->have_fault_thread = false; } - qemu_balloon_inhibit(false); + postcopy_balloon_inhibit(false); if (enable_mlock) { if (os_mlock() < 0) { @@ -1107,7 +1121,7 @@ int postcopy_ram_enable_notify(MigrationIncomingState *mis) * Ballooning can mark pages as absent while we're postcopying * that would cause false userfaults. */ - qemu_balloon_inhibit(true); + postcopy_balloon_inhibit(true); trace_postcopy_ram_enable_notify();